Joolz Day pram - all terrain?

I fell in love with the Joolz Day pram, both for it's good reviews and, if I'm honest, the fact that it looks great! It comes with a hefty price tag which I wasn't sure whether I could justify but I have been offered a second hand one with all the extras for £300. It's in good condition and is only 10 months old.

I have also been given a 2009 Bugaboo Bee for free, which is in good condition and very compact but I don't think this will be much good off road (walks through the woods, beach, moor etc.), so I think we need to get something more robust as well. Would I be mad to think the second hand Joolz Day will do the job if I switch to the all-terrain wheels?

I have a Joolz Geo (i think it has the same wheels as Day, its just the one that converts to a double);and have happily walked it in the woods/thick grass/gravel without the all terrain wheels and it's been great, sturdy and easy to steer. I've had mine 16 months and had no problems with it and it's done many many miles as I don't really drive. The Joolz seem really well built.